Etching composition for thin film containing silver, method for forming pattern and method for manufacturing a display device using the same

ABSTRACT

An etching composition for a silver-containing thin film, the etching composition comprising an inorganic acid compound, a sulfonic acid compound, an organic acid compound, a nitrate, a metal oxidizing agent, an amino acid compound, and water.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2020-0185187, filed on Dec. 28, 2020, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND 1. Field

Embodiments relate to an etching composition. More particularly,embodiments relate to an etching composition for a silver-containingthin film, a method for forming a pattern and a method for manufacturinga display device using the etching composition.

2. Description of the Related Art

An organic light-emitting display device emits light. Organiclight-emitting display devices have a reduced weight and thickness andhave characteristics appropriate for a flexible display device. Usage oforganic light-emitting display devices has increased.

A reflective electrode of the organic light-emitting display device mayinclude silver (Ag). A silver-containing thin film may be etched by wetetching.

When the silver-containing thin film is etched by an etchingcomposition, silver ions may be dissolved in the etching composition.The silver ions dissolved in the etching composition may adsorb to othermetal patterns thereby forming a silver particle. The silver particlemay be transferred to the reflective electrode in other processesthereby causing defects or failure in manufacturing processes.

SUMMARY

Embodiments provide an etching composition for a silver-containing thinfilm.

Embodiments provide a method for forming a pattern using the etchingcomposition.

Embodiments provide a method for manufacturing a display device usingthe etching composition.

According to an embodiment, the etching composition for thesilver-containing thin film may include an inorganic acid compound, asulfonic acid compound, an organic acid compound, a nitrate, a metaloxidizing agent, an amino acid compound, and water.

In an embodiment, the sulfonic acid compound may include at least oneselected from the group consisting of methanesulfonic acid,ethanesulfonic acid, p-toluenesulfonic acid, benzenesulfonic acid, aminomethylsulfonic acid, and sulfamic acid.

In an embodiment, the organic acid compound may include at least oneselected from the group consisting of acetic acid, citric acid, glycolicacid malonic acid, lactic acid, tartaric acid, butanoic acid, formicacid, gluconic acid, oxalic acid, pentanoic acid, sulfobenzoic acid,sulfosuccinic acid, sulfophthalic acid, salicylic acid, sulfosalicylicacid, benzoic acid, glyceric acid, succinic acid, malic acid, isocitricacid, propenoic acid, iminodiacetic acid and ethylenediaminetetraaceticacid.

In an embodiment, the nitrate may include at least one selected from thegroup consisting of sodium nitrate, potassium nitrate, ammonium nitrate,calcium nitrate, magnesium nitrate, and aluminum nitrate.

In an embodiment, the metal oxidizing agent may include at least oneselected from the group consisting of ferric nitrate, ferric sulfate,copper, and copper sulfate.

In an embodiment, the amino acid compound may include at least oneselected from the group consisting of glycine, alanine, valine, leucine,isoleucine, serine, threonine, aspartic acid, cysteine, and methionine.

In an embodiment, the inorganic acid compound may include nitric acid.

In an embodiment, the etching composition may include 1 wt % to 13 wt %of the inorganic acid compound, 0.1 wt % to 7 wt % of the sulfonic acidcompound, 30 wt % to 55 wt % of the organic acid compound, 1 wt % to 17wt % of the nitrate, 0.01 wt % to 0.09 wt % of the metal oxidizingagent, 0.1 wt % to 7 wt % of the amino acid compound, and a remainder ofthe etching composition may include water.

In an embodiment, the inorganic acid compound may include nitric acid,the sulfonic acid compound may include methanesulfonic acid, the organicacid compound may include citric acid and acetic acid, the nitrate mayinclude calcium nitrate and ammonium nitrate, the metal oxidizing agentmay include ferric nitrate, and the amino acid compound may includeglycine.

In an embodiment, the etching composition may not include ammoniumbisulfate.

In an embodiment, the etching composition may not include phosphoricacid.

According to an embodiment, the method for forming the pattern mayinclude forming a multilayer including a silver-containing thin film anda metal oxide thin film. The metal oxide thin film is etched using afirst etching composition. The silver-containing thin film is etchedusing a second etching composition comprising an inorganic acidcompound, a sulfonic acid compound, an organic acid compound, a nitrate,a metal oxidizing agent, an amino acid compound, and water.

In an embodiment, the second etching composition may include 1 wt % to13 wt % of the inorganic acid compound, 0.1 wt % to 7 wt % of thesulfonic acid compound, 30 wt % to 55 wt % of the organic acid compound,1 wt % to 17 wt % of the nitrate, 0.01 wt % to 0.09 wt % of the metaloxidizing agent, 0.1 wt % to 7 wt % of the amino acid compound, and aremainder of the second etching composition may include water.

In an embodiment, the inorganic acid compound may include nitric acid,the sulfonic acid compound may include methanesulfonic acid, the organicacid compound may include citric acid and acetic acid, the nitrate mayinclude calcium nitrate and ammonium nitrate, the metal oxidizing agentmay include ferric nitrate, and the amino acid compound may includeglycine.

According to an embodiment, the method for manufacturing the displaydevice may include forming an active pattern in a display area on a basesubstrate. A gate metal pattern including a gate electrode overlappingthe active pattern is formed. A source metal pattern including aconnection pad disposed in a peripheral area surrounding the displayarea is formed. A multiple layer on the source metal pattern is formed.The multiple layer includes a lower layer including a metal oxide, anintermediate layer disposed on the lower layer and including silver or asilver alloy, and an upper layer disposed on the intermediate layer andincluding a metal oxide. The upper layer is etched using a first etchingcomposition. The intermediate layer is etched using a second etchingcomposition comprising an inorganic acid compound, a sulfonic acidcompound, an organic acid compound, a nitrate, a metal oxidizing agent,an amino acid compound, and water. The lower layer is etched using athird etching composition to form an electrode pattern in the displayarea and to expose the connection pad.

In an embodiment, the source metal pattern may have a single-layerstructure or a multiple-layer structure, the source metal patternincluding aluminum.

In an embodiment, the metal oxide may include at least one selected fromthe group consisting of indium oxide, zinc oxide, tin oxide, indium tinoxide and indium zinc oxide.

In an embodiment, the second etching composition may include 1 wt % to13 wt % of the inorganic acid compound, 0.1 wt % to 7 wt % of thesulfonic acid compound, 30 wt % to 55 wt % of the organic acid compound,1 wt % to 17 wt % of the nitrate, 0.01 wt % to 0.09 wt % of the metaloxidizing agent, 0.1 wt % to 7 wt % of the amino acid compound, and aremainder of the second etching composition may include water.

In an embodiment, the inorganic acid compound may include nitric acid,the sulfonic acid compound may include methanesulfonic acid, the organicacid compound may include citric acid and acetic acid, the nitrate mayinclude calcium nitrate and ammonium nitrate, the metal oxidizing agentmay include ferric nitrate, and the amino acid compound may includeglycine.

In an embodiment, the method may further include connecting a drivingchip, which generates a driving signal, to the connection pad.

According to the embodiments, etching compositions may have selectivityfor a silver-containing thin film with respect to a metal oxide such asindium oxide, and may prevent damage of other metal layers includingaluminum or the like, and may prevent reductive precipitation of silverparticles.

Furthermore, when etching a silver-containing thin film, the etchingcomposition may prevent etching residues from occurring and may form aCD-skew having an appropriate length.

Furthermore, the stability of the etching compositions for cumulativeuse and over time may be improved.

Thus, defects in manufacturing processes for a display device may bereduced, and the reliability of the display device may be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

Features will become apparent to those of skill in the art by describingin detail embodiments with reference to the attached drawings.

FIG. 1 illustrates a plan view of a display device manufacturedaccording to an embodiment.

FIGS. 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11 illustrate cross-sectionalviews of stages of a method for manufacturing a display device accordingto an embodiment.

FIG. 12 illustrates a cross-sectional view of a display devicemanufactured according to an embodiment.

DETAILED DESCRIPTION

An etching composition for a silver-containing thin film, a method forforming a pattern and a method for manufacturing a display deviceaccording to embodiments will be described hereinafter with reference tothe accompanying drawings, in which some embodiments are shown. Same orsimilar reference numerals may be used for same or similar elements inthe drawings.

An Etching Composition for a Silver-Containing Thin Film

An etching composition according to an embodiment may include aninorganic acid compound, a sulfonic acid compound, an organic acidcompound, a nitrate, a metal oxidizing agent, an amino acid compound,and water. The etching composition may be used for etching asilver-containing thin film, which contains silver or a silver alloy.Accordingly, a multilayer structure may be etched by dividing theoperations.

The inorganic acid compound may include nitric acid. The nitric acid mayact as a main oxidizing agent for the silver (Ag) component. Inaddition, the nitric acid may also act as an oxidizing agent for atransparent conductive layer. The transparent conductive layer mayinclude indium tin oxide (“ITO”), indium zinc oxide (“IZO”), indiumgallium oxide (“IGO”), indium zinc oxide (“ITZO”), indium gallium zincoxide (“IGZO”), and the like.

In embodiments, a content of nitric acid may be about 1.0 wt % to about13.0 wt %, suitably about 5.0 wt % to about 11.0 wt %. If the content ofnitric acid is higher than 13.0 wt %, an etching rate is too high, andit is difficult to control the degree of etching, so that a target thinfilm may be overetched. If the nitric acid is less than 1.0 wt %, theetching rate may decrease, and thus sufficient etching may not beperformed. When the content of nitric acid is adjusted within the abovecontent range, it is easy to control the etching rate using the etchingcomposition, and the target thin film can be uniformly etched.

The sulfonic acid compound may serve as an etching aid for the silvercomponent, may increase the silver etching rate, and prevent a silverresidue. In addition, the sulfonic acid compound may reduce adecomposition rate of the inorganic acid compound to maintain a constantetching rate of the silver-containing thin film.

In embodiments, the content of the sulfonic acid compound may be about0.1 wt % to about 7.0 wt %, suitably about 2.0 wt % to about 6.0 wt %.If a content of the sulfonic acid compound is higher than 7.0 wt %, anetching rate of the silver-containing thin film may be excessivelyincreased, resulting in poor erosion. If the content of the sulfonicacid compound is less than 0.1 wt %, a decomposition rate of theinorganic acid compound may increase, thereby impairing the stability ofthe etching composition, and a silver residue may occur.

Examples of the sulfonic acid compound include methanesulfonic acid(CH₃SO₃H), ethanesulfonic acid (CH₃CH₂SO₃H), p-toluenesulfonic acid(CH₃C₆H₄SO₃H), benzenesulfonic acid (C₆H₅SO₃H), amino methylsulfonicacid (CH₅NO₃S), sulfamic acid (H₃NSO₃), and the like, and these may beused alone or in combination. In embodiments, it may be desirable toinclude methanesulfonic acid in the etching composition.

The organic acid compound may serve as an etchant for thesilver-containing thin film. The organic acid compound may be used toetch the silver-containing thin film oxidized by the nitric acid.

In embodiments, a content of the organic acid compound may be about 30.0wt % to about 55.0 wt %, suitably about 40.0 wt % to about 55.0 wt %. Ifthe content of the organic acid compound is higher than 55.0 wt %, anetching rate of the silver-containing thin film may be excessivelyincreased, resulting in poor erosion. If the content of the organic acidcompound is less than 30.0 wt %, a decomposition rate of the organicacid compound may increase, thereby impairing the stability of theetching composition, and a silver residue may occur. If the content ofthe organic acid compound is controlled within the above content range,it is easy to control the rate of etching using the etching composition,and it is possible to prevent silver residue and silver re-adsorptionaccordingly.

Examples of the organic acid compound may include at least one or two ormore substances selected from the group including acetic acid (CH₃COOH),citric acid (C₆H₈O₇), glycolic acid (CH₂OHCOOH), malonic acid (C₃H₄O₄),lactic acid (C₃H₆O₃), tartaric acid (C₄H₆O₆), butaonic acid(CH₃CH₂CH₂COOH), formic acid (HCOOH), gluconic acid (C₆H₁₂O₇), oxalicacid (C₂H₂O₄), pentanic acid (CH₃(CH₂)₃COOH), sulfobenzoic acid,sulfosuccinic acid (C₄H₆O₇S), sulfophthalic acid, salicylic acid(C₇H₆O₃), sulfosalicylic acid dehydrate (C₇H₆O₆S), benzoic acid(C₇H₆O₂), glyceric acid, succinic acid ((CH₂)₂(CO₂H)₂), malic acid(C₄H₆O₅), isoctric acid (C₆H₈O₇), propenoic acid, iminodiacetic acid,HN(CH₂CO₂H)₂), ethylenediaminetetraacetic acid (C₁₀H₁₆N₂O₈), and thelike. Suitably, the organic acid compound may include one or two or moresubstances selected from acetic acid, citric acid, glycolic acid,malonic acid, lactic acid, and tartaric acid.

The nitrate is a remover for removing the silver residue, and may serveto remove the silver residue. Compared with other salts such as sulfate,the nitrate has a high oxidation potential and may relatively easilyoxidize silver and other metals. Since the etching composition includesthe nitrate, an etching rate may be controlled, and a side etching ofthe silver-containing thin film may be controlled.

The etching composition according to embodiments may be used to etchmultilayer films containing silver such as ITO/Ag/ITO by dividing theetching into three operations. That is, the etching composition may beused to etch a layer containing silver in a process of sequentiallyetching ITO, Ag, and ITO. In this case, when the etching compositionincludes sulfate, the sulfate may remove silver and simultaneously etchITO. Accordingly, the etching composition may secure a high selectivityto silver by including nitrate instead of sulfate having a highoxidation potential.

In embodiments, a content of the nitrate may be about 1.0 wt % to about17.0 wt %, suitably about 5.0 wt % to about 15.0 wt %. When a content ofthe nitrate is controlled within the above content range, it is easy tocontrol an etching time using the etching composition, and thesilver-containing thin film can be uniformly etched.

Examples of the nitrate may include at least one selected from the groupincluding sodium nitrate, potassium nitrate, ammonium nitrate, calciumnitrate, magnesium nitrate, aluminum nitrate, and the like. Suitably,the nitrate may include calcium nitrate.

The metal oxidizing agent may increase the etching rate for the silvercomponent. According to embodiments, the content of the metal oxidizingagent may be about 0.01 wt % to about 0.09 wt %, suitably about 0.02 wt% to about 0.06 wt %. When a content of the metal oxidizing agent ishigher than 0.09 wt %, the etching rate of the silver-containing thinfilm is excessively increased, so that the CD-skew may be excessivelyincreased, where the CD-skew is the distance between an end of aphotoresist pattern used to etch the silver-containing film and an endof the silver containing film (Ag layer). In addition, when the contentof the metal oxidizing agent is lower than 0.01 wt %, an etching rate ofthe silver-containing thin film is excessively decreased, and a residuemay be generated.

The metal oxidizing agent may be at least one selected from the groupincluding metals such as iron and copper, or metal salts such as iron,copper, aluminum, molybdenum, chromium, and manganese. In embodiments,the metal oxidizing agent may include at least one selected from a groupincluding ferric nitrate, ferric sulfate, copper, and copper sulfate.

The amino acid compound may serve as an auxiliary agent for increasingthe number of sheets of the silver-containing thin film that can beprocessed using the etching composition. The amino acid compound mayinhibit the activity of silver ions by combining the silver ionsdissolved in the etching solution after etching the silver-containingthin film. Accordingly, it is possible to minimize a change in thecharacteristics of the etchant, and accordingly, the etchant can becontinuously used.

In embodiments, a content of the amino acid compound may be about 0.1 wt% to about 7.0 wt %, suitably about 0.5 wt % to about 5.0 wt %. When acontent of the amino acid compound is controlled within the abovecontent range, it is possible to easily control the number of processedsheets of the silver-containing thin film, reduce the amount of lateraletching, and minimize defects caused by re-adsorption of silver. Forexample, a variation amount of the side etching may mean a difference inthe degree to which the side is etched when etching a plurality ofsilver-containing thin films.

The amino acid compound may include at least one selected from the groupincluding glycine, alanine, valine, leucine, isoleucine, serine,threonine, aspartic acid, cysteine, methionine, and the like. Suitably,the amino acid compound may include glycine and alanine.

A content of water may correspond to the remainder of the etchingcomposition, excluding the content of nitric acid, sulfonic acidcompound, organic acid compound, nitrate compound, metal oxidizingagent, and amino acid compound. Water may be deionized water forsemiconductor processing. Suitably, deionized water of 1 MΩ/cm or moremay be used as the water.

Suitably, the etching composition is substantially free of phosphoricacid. Phosphoric acid may cause damage to metals that are not to beetched, such as aluminum, and may increase process defects by increasingthe reductive precipitation of silver.

In addition, phosphoric acid may etch metal oxides such as indium tinoxide. By excluding phosphoric acid, the etching composition mayselectively etch silver in a multilayer structure including a metaloxide such as indium tin oxide.

Method for Manufacturing a Display Device

FIG. 1 is a plan view illustrating a display device 100 manufacturedaccording to an embodiment. FIGS. 2 to 11 are cross-sectional viewsillustrating a method for manufacturing a display device according to anembodiment. FIG. 12 is a cross-sectional view illustrating a displaydevice manufactured according to an embodiment.

Referring to FIG. 1, the display device 100 includes a display area 10and a peripheral area 20 surrounding the display area 10.

In the peripheral area 20, connection pads CP electrically connected toan external device may be disposed. For example, the connection pads CPmay be connected to a driving chip 400 providing a driving signal suchas a data signal, a gate signal or the like. The driving signal providedby the driving chip 400 may be transferred to pixels PX in the displayarea 10 through the connection pads CP.

In an embodiment, the display device 100 may be an organiclight-emitting display device. For example, an array of the pixels PXmay be disposed in the display area 10, and each of the pixels PX mayinclude an organic light-emitting diode and a circuit part for drivingthe organic light-emitting diode.

Referring to FIG. 2, a buffer layer 120 is formed on a base substrate110.

For example, the base substrate 110 may include glass, quartz, silicon,a polymer or the like. For example, the polymer may include polyethyleneterephthalate, polyethylene naphthalate, polyether ketone,polycarbonate, polyarylate, polyether sulfone, polyimide or acombination thereof.

The buffer layer 120 may prevent or reduce penetration of impurities,humidity or external gas from underneath the base substrate 110, and mayplanarize an upper surface of the base substrate 110. For example, thebuffer layer 120 may include an inorganic material such as oxide,nitride or the like.

An active pattern AP is formed on the buffer layer 120 in the displayarea 10.

For example, the active pattern AP may include a semiconductive materialsuch as amorphous silicon, polycrystalline silicon (polysilicon), ametal oxide or the like. In an embodiment, the active pattern AP mayinclude polysilicon. At least a portion of the active pattern APincluding polysilicon may be doped with impurities such as n-typeimpurities or p-type impurities.

Referring to FIG. 3, a first insulation layer 130 is formed on theactive pattern AP. For example, the first insulation layer 130 mayinclude silicon oxide, silicon nitride, silicon carbide or a combinationthereof. Furthermore, the first insulation layer 130 may include aninsulating metal oxide such as aluminum oxide, tantalum oxide, hafniumoxide, zirconium oxide, titanium oxide or the like. For example, thefirst insulation layer 130 may have a single-layer structure or amultiple-layer structure including silicon nitride and/or silicon oxide.

A gate metal pattern including a gate electrode GE and a connection lineCL is formed on the first insulation layer 130.

For example, the gate metal pattern may include gold (Au), silver (Ag),aluminum (Al), copper (Cu), nickel (Ni), platinum (Pt), magnesium (Mg),chromium (Cr), tungsten (W), molybdenum (Mo), titanium (Ti), tantalum(Ta) or an alloy thereof, and may have a single-layer structure or amultiple-layer structure including different metal layers.

The connection line CL may be disposed in the peripheral area 20, andmay extend into the display area 10.

In an embodiment, after the gate electrode GE is formed, a portion ofthe active pattern AP may be doped with impurities through anion-implantation process.

Referring to FIG. 4, a second insulation layer 140 is formed to coverthe gate metal pattern and the first insulation layer 130.

For example, the second insulation layer 140 may include silicon oxide,silicon nitride, silicon carbide or a combination thereof. Furthermore,the second insulation layer 140 may include an insulating metal oxidesuch as aluminum oxide, tantalum oxide, hafnium oxide, zirconium oxide,titanium oxide or the like. For example, the second insulation layer 140have a single-layer structure or a multiple-layer structure includingsilicon nitride and/or silicon oxide.

Referring to FIG. 5, a source metal pattern including a source electrodeSE, a drain electrode DE and a connection pad CP is formed on the secondinsulation layer 140.

The source electrode SE and the drain electrode DE may respectively passthrough the first and second insulation layers 130 and 140 to contactthe active pattern AP.

The connection pad CP is disposed in the peripheral area 20, and maypass through the second insulation layer 140 to contact the connectionline CL.

For example, the source metal pattern may include gold (Au), silver(Ag), aluminum (Al), copper (Cu), nickel (Ni), platinum (Pt), magnesium(Mg), chromium (Cr), tungsten (W), molybdenum (Mo), titanium (Ti),tantalum (Ta) or an alloy thereof, and may have a single-layer structureor a multiple-layer structure including different metal layers. In anembodiment, the source metal pattern may include aluminum. For example,the source metal pattern may have a double-layer structure oftitanium/aluminum or a triple-layer structure oftitanium/aluminum/titanium.

Referring to FIG. 6, a third insulation layer 150 is formed to cover thesource electrode SE and the drain electrode DE. In an embodiment, theconnection pad CP is not covered by the third insulation layer 150 sothat an entire supper surface of the connection pad CP is exposed. Thethird insulation layer 150 includes an opening exposing at least aportion of the drain electrode DE.

For example, the third insulation layer 150 may include an inorganicinsulation material, an organic insulation material or a combinationthereof. For example, the organic insulation material may include aphenol resin, an acryl resin, a polyimide resin, a polyamide resin, anepoxy resin, benzocyclobetene or the like.

A lower electrode layer 211 is formed on the connection pad CP and thethird insulation layer 150. The lower electrode layer 211 may include ametal, a metal alloy, a metal oxide or a combination thereof.

For example, the lower electrode layer 211 may have a multiple-layerstructure including a metal oxide layer and a metal layer. The metaloxide layer may include indium oxide, zinc oxide, tin oxide, indium tinoxide, indium zinc oxide, zinc tin oxide or the like. The metal layermay include gold (Au), silver (Ag), aluminum (Al), copper (Cu), nickel(Ni), platinum (Pt), magnesium (Mg), chromium (Cr), tungsten (W),molybdenum (Mo), titanium (Ti), tantalum (Ta) or an alloy thereof.

In an embodiment, the lower electrode layer 211 may have amultiple-layer structure including a lower layer 211 a, an intermediatelayer 211 b and an upper layer 211 c. In an embodiment, the lower layer211 a and the upper layer 211 c may include indium tin oxide, and theintermediate layer 211 b may include silver.

The lower electrode layer 211 may contact the drain electrode DE throughthe opening of the third insulation layer 150. A photoresist pattern PRoverlapping the drain electrode DE is formed on the lower electrodelayer 211.

Referring to FIG. 7, the upper layer 211 c of the lower electrode layer211 is etched using the photoresist pattern PR as a mask to form anupper pattern 212. Thus, the upper pattern 212 is formed under thephotoresist pattern PR, and the remainder of the upper layer 211 c isremoved to expose an upper surface of the intermediate layer 211 b.

The upper layer 211 c including indium tin oxide may be wet-etched usinga first etching composition.

In an embodiment, the first etching composition may include nitric acid,a chlorinated compound, an ammonium compound, a cyclic amine compound,and water.

Examples of the chlorinated compound may include sodium chloride,potassium chloride, ammonium chloride and the like. These may be usedeach alone or in combination thereof.

Examples of the ammonium compound may include ammonium acetate, ammoniumsulfamate, ammonium benzenediol, ammonium carbanate, ammonium dihydrogenphosphate, ammonium formate, ammonium bicarbonate, ammonium citrate,ammonium nitrate, ammonium persulfate, ammonium sulphamate, ammoniumsulfate and the like. These may be used each alone or in combinationthereof.

Examples of the cyclic amine compound may include benzotriazole,5-aminotetrazole, 3-aminotetrazole, 5-methyltetrazole and the like.These may be used each alone or in combination thereof.

For example, the first etching composition may include 3 wt % to 10 wt %of nitric acid, 0.01 wt % to 5 wt % of the chlorinated compound, 0.1 wt% to 5 wt % of the ammonium compound, 0.1 wt % to 5 wt % of the cyclicamine compound, and a remainder of water.

In an embodiment, the first etching composition may include nitric acid,sulfuric acid, an ammonium compound, a cyclic amine compound and water.For example, the first etching composition may include 1 wt % to 10 wt %of nitric acid, 1 wt % to 10 wt % of sulfuric acid, 0.1 wt % to 5 wt %of the ammonium compound, 0.1 wt % to 5 wt % of the cyclic aminecompound and a remainder of water.

Referring to FIG. 8, the intermediate layer 211 b of the lower electrodelayer 211 is etched using the photoresist pattern PR as a mask to forman intermediate pattern 214. Thus, the intermediate pattern 214 isformed under the upper pattern 212 and the photoresist pattern PR, andthe remainder of the intermediate layer 211 b is removed to expose anupper surface of the lower layer 211 c.

The intermediate layer 211 b containing silver may be wet-etched using asecond etching composition.

In an embodiment, the second etching composition may have a samecomposition as the previously explained etching composition for asilver-containing thin film. For example, the second etching compositionmay include an inorganic acid compound, a sulfonic acid compound, anorganic acid compound, a nitrate, a metal oxidizing agent, an amino acidcompound, and water.

Referring to FIG. 9, the lower layer 211 a of the lower electrode layer211 is etched using the photoresist pattern PR as a mask to form a lowerpattern 216. Thus, a lower electrode 210 including the lower pattern216, the intermediate pattern 214 and the upper pattern 212 is formedunder the photoresist pattern PR. The lower pattern 216 contacts thedrain electrode DE.

In an embodiment, the lower layer 211 a including indium tin oxide maybe wet-etched using a third etching composition. For example, the thirdetching composition may have a substantially same composition as thefirst etching composition.

In an embodiment, the lower electrode 210 may be an anode of an organiclight-emitting diode. The remainder of the lower layer 211 a excludingthe lower pattern 216 may be removed to expose the connection pad CP.

Referring to FIG. 10, a pixel-defining layer 160 may be formed on thethird insulation layer 150. The pixel-defining layer 160 may include anopening that exposes at least a portion of the lower electrode 210. Forexample, the pixel-defining layer 160 may include an organic insulationmaterial.

An organic light-emitting layer 220 is formed on the lower electrode210. For example, the organic light-emitting layer 220 may be disposedin the opening of the pixel-defining layer 160. However, in embodiments,the organic light-emitting layer 220 may extend over an upper surface ofthe pixel-defining layer 160, or may continuously extend over aplurality of the pixels in the display area 10.

The organic light-emitting layer 220 may include at least alight-emitting layer, and may further include at least one of ahole-injection layer (HIL), a hole-transporting layer (HTL), anelectron-transporting layer (ETL) and an electron-injection layer (EIL).For example, the organic light-emitting layer 220 may include a lowmolecular weight organic compound or a high molecular weight organiccompound.

In an embodiment, the organic light-emitting layer 220 may emit a redlight, a green light or a blue light. In an embodiment, the organiclight-emitting layer 220 may emit a white light. The organiclight-emitting layer 220 emitting a white light may have amultiple-layer structure including a red-emitting layer, agreen-emitting layer and a blue-emitting layer, or a single-layerstructure including a mixture of a red-emitting material, agreen-emitting material and a blue-emitting material.

An upper electrode 230 is formed on the organic light-emitting layer220. In an embodiment, the upper electrode 230 may continuously extendover a plurality of the pixels in the display area 10.

In an embodiment, the upper electrode 230 may function as a cathode. Forexample, the upper electrode 230 may be formed as a transmittingelectrode or a reflecting electrode according to an emission type of thedisplay device. For example, when the upper electrode 230 is atransmitting electrode, the upper electrode 230 may include lithium(Li), calcium (Ca), lithium fluoride (LiF), aluminum (Al), magnesium(Mg), or a combination thereof, and the display device may furtherinclude a sub electrode or a bus electrode line, which includes indiumtin oxide, indium zinc oxide, zinc tin oxide, indium oxide, zinc oxide,tin oxide or the like.

In an embodiment, a thin-film encapsulation layer 300 may be formed onthe upper electrode 230. The thin-film encapsulation layer 300 may havea stack structure of an inorganic layer and an organic layer.

Even though not illustrated, a capping layer and a blocking layer may bedisposed between the upper electrode 230 and the thin-film encapsulationlayer 300.

Referring to FIG. 11, the connection pad CP is connected to a drivingchip 400. For example, the connection pad CP is connected to the drivingchip 400 through a conductive bump 410.

As previously explained, the connection pad CP formed in the peripheralarea 20 of the display device may be exposed without a passivation layercovering the connection pad CP in the process of etching the lowerelectrode layer 211. Thus, when a conventional etching compositionincluding phosphoric acid is used, silver particles may be generated dueto the exposed connection pad CP. The silver particles may betransferred to the lower electrode in the following processes includinga stripping process, a rinsing process or the like thereby causingdefects of the display device.

Etching compositions according to embodiments may have selectivity for asilver-containing thin film with respect to a metal oxide such as indiumoxide, and may prevent damage of other metal layers including aluminumor the like, and may prevent reductive precipitation of silverparticles.

Furthermore, when etching a silver-containing thin film, the etchingcomposition may prevent etching residues and may form a CD-skew havingappropriate length.

Furthermore, the stability of the etching compositions for cumulativeuse and over time may be improved.

Thus, defects in manufacturing processes for a display device may bereduced, and the reliability of the display device may be improved.

In an embodiment, the lower electrode 210 of the organic light-emittingdiode may contact the drain electrode DE. However, in an embodiment, asillustrated in FIG. 12, the lower electrode 210 of the organiclight-emitting diode may be electrically connected to the drainelectrode DE through a connection electrode CE. The connection electrodeCE may pass through the third insulation layer 150 to contact the drainelectrode DE. A fourth insulation layer 170 may be disposed between thethird insulation layer 150 and a pixel-defining layer 160, and the lowerelectrode 210 may pass through the fourth insulation layer 170 tocontact the connection electrode CE.

In an embodiment, the connection pad CP disposed in the peripheral area20 and electrically connected to the driving chip 400 through theconductive bump 410 may be formed from a same layer as the drainelectrode DE. However, in an embodiment, the connection pad CP may beformed from a same layer as the connection electrode CE.

Hereinafter, effects of embodiments will be explained with reference toexperiments and examples.

Examples and Comparative Examples

Etching compositions for Examples and Comparative Examples were preparedaccording to the following Tables 1 and 2. In Table 1, the unit of thecontent is wt % and the remainder of the etching compositions was water.

TABLE 1 A B C1 C2 D1 D2 E F G Example1 7 5 30 20 10 0 0.03 2 0 Example27 5 30 20 15 0 0.03 2 0 Example3 9 5 30 20 10 0 0.03 0.5 0 Example4 7 530 20 0 10 0.03 2 0 Example5 7 5 30 20 10 0 0.03 0.5 0 Comparative 7 530 20 0 0 0.03 2 10 Example 1 Comparative 7 5 30 20 0 0 0.03 2 0 Example2 Comparative 7 5 30 20 0.5 0 0.03 2 0 Example 3 Comparative 7 5 30 2010 0 0.03 0.01 0 Example 4 Comparative 7 5 30 20 10 0 0.03 15 0 Example5

TABLE 2 Component Name of component A nitric acid B Methanesulfonic acidC1 Citric acid C2 Acetic acid D1 Calcium nitrate D2 Ammonium nitrate EFerric nitrate F Glycine G Ammonium bisulfate

Experiment 1—Evaluation of Etching Characteristics

A double film of ITO/Ag was formed on a glass substrate, and aphotoresist pattern was formed on the double film.

The results of etching the Ag layer (silver-containing thin film layer)with the etching compositions of Examples 1 to 5 and ComparativeExamples 1 to 5 are shown in Table 3 below.

TABLE 3 New Etching Solution (Ag 0 ppm) Old Etching Solution (Ag 2,000ppm) CD-skew CD-skew Ag Ag ITO CD-skew Ag Ag ITO variation (one side)residue resorption E/R (one side) residue resorption E/R (one side)Example1 excellent good good good excellent good good good greatExample2 excellent good good good excellent good good good greatExample3 great good good good great good good good great Example4 greatgood good good great good good good great Example5 excellent good goodgood excellent good good good great Comparative great good bad bad greatgood bad bad great Example 1 Comparative great bad good good bad badgood good great Example 2 Comparative good bad good good good bad goodgood great Example 3 Comparative great good good good good good goodgood bad Example 4 Comparative great bad good good great bad good goodgreat Example 5

Referring to Table 3, the experiment was conducted under two conditionsat about 40 degrees Celsius. In embodiments, when the etchingcomposition is used for the first time, silver is not dissolved in theetching composition. Therefore, the experiment was conducted with a newetching solution in which silver was not dissolved (Ag 0 ppm).

In embodiments, the etching composition may be repeatedly used in anetching apparatus. Accordingly, silver etched by the etching compositionmay be dissolved in the etching composition. Therefore, the experimentwas conducted even with the old etching solution (Ag 2,000 ppm) in whichsilver was dissolved.

In the case of using the etching compositions of Examples 1 to 5, theCD-skew (distance between an end of the photoresist pattern and an endof the Ag layer) was evaluated as great or higher for both the new andold etching solutions. In detail, for Examples 1, 2 and 5, the CD-skewwas evaluated excellent, and for Examples 3 and 4, the CD-skew wasevaluated great. Excellent CD-skew means that the CD-skew is measured tobe less than 0.2 micrometers. Great CD-skew means that the CD-skew ismore than 0.2 micrometers and measured less than 0.4 micrometers.

For both the new etchant and the old etchant, the measurement result ofAg residue and Ag resorption was determined to be good. When the resultof the Ag residue was measured as good, it means that no Ag residue wasgenerated. In addition, the fact that the results for Ag re-adsorptionwere determined to be good means that the number of silver particles wasre-adsorbed to less than 5 on the glass substrate.

CD-skew variation refers to the difference between the CD-skew whenusing the new etchant and the old etchant. For Examples 1 to 5, all ofthe variations in CD-skew were evaluated as great. The great variationof the CD-skew means that the difference is more than 0.05 micrometersand less than 0.1 micrometers.

However, in Comparative Example 1 containing ammonium bisulfate withoutcalcium nitrate and ammonium nitrate, Ag re-adsorption occurred. Inaddition, in Comparative Example 2 that did not contain calcium nitrateand ammonium nitrate, Ag residue was generated, and the CD-skew wasevaluated as bad. A bad CD-skew means that the CD-skew is 0.6micrometers or more.

In addition, in Comparative Example 3 containing only calcium nitrate ina small amount (for example, 0.5 wt %), an Ag residue was generated, andthe CD-skew was evaluated as good. Good CD-skew means CD-skew is greaterthan 0.4 micrometers and less than 0.6 micrometers.

In addition, in Comparative Example 4 containing less glycine, theCD-skew was evaluated as good for the old etchant.

In Comparative Example 5 containing an excessive amount of glycine, thesilver residue was evaluated as bad. When the above-described silverresidue is bad, it means that silver residue has occurred. Theoccurrence of the above-described silver residue means that the silverremains without being etched in the portion not covered with thephotoresist.

ITO E/R (ITO ETCH RATE) was evaluated as good for both Examples 1 to 5and Comparative Examples 2 to 5. Good ITO E/R means that ITO disposedunder the silver-containing thin film is etched at a rate of 0.3 Å/secor less. However, in the case of Comparative Example 1, since itcontained ammonium bisulfate, ITO E/R was evaluated as bad. The bad ITOE/R means that the ITO disposed under the silver-containing thin film isetched at a rate of 0.4 Å/sec or more.

Since the etching composition is provided only for a limited time duringthe etching of the silver-containing thin film, in the case of usingExamples 1 to 5, the silver-containing thin film can be etched whileminimizing the etching of ITO. Through this, the embodiments may etchthe silver-containing thin film and ITO by dividing the etchingoperations.

Embodiments may be used for etching a silver-containing thin film or amultiple layer including the silver-containing thin film. For example,embodiments may be used for forming wirings or electrodes, or formanufacturing various electronic devices including the wirings or theelectrodes.

The foregoing is illustrative of embodiments and is not to be construedas limiting thereof. Although embodiments have been described, thoseskilled in the art will readily appreciate that many modifications arepossible in the embodiments without materially departing from the novelteachings and aspects of the present inventive concept. Accordingly, allsuch modifications are intended to be included within the scope of thepresent inventive concept. Therefore, it is to be understood that theforegoing is illustrative of various embodiments and is not to beconstrued as limited to the specific embodiments disclosed, and thatmodifications to the disclosed embodiments, as well as otherembodiments, are intended to be included within the scope of the presentinventive concept, as set forth in the following claims and equivalentsthereof.

What is claimed is:
 1. An etching composition for a silver-containingthin film, the etching composition comprising an inorganic acidcompound, a sulfonic acid compound, an organic acid compound, a nitrate,a metal oxidizing agent, an amino acid compound, and water.
 2. Theetching composition of claim 1, wherein the sulfonic acid compoundcomprises at least one selected from the group consisting ofmethanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid,benzenesulfonic acid, amino methylsulfonic acid, and sulfamic acid. 3.The etching composition of claim 1, wherein the organic acid compoundcomprises at least one selected from the group consisting of aceticacid, citric acid, glycolic acid malonic acid, lactic acid, tartaricacid, butanoic acid, formic acid, gluconic acid, oxalic acid, pentanoicacid, sulfobenzoic acid, sulfosuccinic acid, sulfophthalic acid,salicylic acid, sulfosalicylic acid, benzoic acid, glyceric acid,succinic acid, malic acid, isocitric acid, propenoic acid, iminodiaceticacid and ethylenediaminetetraacetic acid.
 4. The etching composition ofclaim 1, wherein the nitrate comprises at least one selected from thegroup consisting of sodium nitrate, potassium nitrate, ammonium nitrate,calcium nitrate, magnesium nitrate, and aluminum nitrate.
 5. The etchingcomposition of claim 1, wherein the metal oxidizing agent comprises atleast one selected from the group consisting of ferric nitrate, ferricsulfate, copper, and copper sulfate.
 6. The etching composition asclaimed in claim 1, wherein the amino acid compound comprises at leastone selected from the group consisting of glycine, alanine, valine,leucine, isoleucine, serine, threonine, aspartic acid, cysteine, andmethionine.
 7. The etching composition of claim 1, wherein the inorganicacid compound comprises nitric acid.
 8. The etching composition of claim1, comprising: 1 wt % to 13 wt % of the inorganic acid compound, 0.1 wt% to 7 wt % of the sulfonic acid compound, 30 wt % to 55 wt % of theorganic acid compound, 1 wt % to 17 wt % of the nitrate, 0.01 wt % to0.09 wt % of the metal oxidizing agent, 0.1 wt % to 7 wt % of the aminoacid compound, and a remainder of the etching composition being water.9. The etching composition of claim 1, wherein: the inorganic acidcompound comprises nitric acid, the sulfonic acid compound comprisesmethanesulfonic acid, the organic acid compound comprises citric acidand acetic acid, the nitrate comprises calcium nitrate and ammoniumnitrate, the metal oxidizing agent comprises ferric nitrate, and theamino acid compound comprises glycine.
 10. The etching composition ofclaim 9, wherein the etching composition does not include ammoniumbisulfate.
 11. The etching composition of claim 9, wherein the etchingcomposition does not include phosphoric acid.
 12. A method for forming apattern, the method comprising: forming a multilayer comprising asilver-containing thin film and a metal oxide thin film; etching themetal oxide thin film using a first etching composition; and etching thesilver-containing thin film using a second etching compositioncomprising an inorganic acid compound, a sulfonic acid compound, anorganic acid compound, a nitrate, a metal oxidizing agent, an amino acidcompound and water.
 13. The method of claim 12, wherein the secondetching composition comprises: 1 wt % to 13 wt % of the inorganic acidcompound, 0.1 wt % to 7 wt % of the sulfonic acid compound, 30 wt % to55 wt % of the organic acid compound, 1 wt % to 17 wt % of the nitrate,0.01 wt % to 0.09 wt % of the metal oxidizing agent, 0.1 wt % to 7 wt %of the amino acid compound, and a remainder of the second etchingcomposition being water.
 14. The method of claim 12, wherein: theinorganic acid compound comprises nitric acid, the sulfonic acidcompound comprises methanesulfonic acid, the organic acid compoundcomprises citric acid and acetic acid, the nitrate comprises calciumnitrate and ammonium nitrate, the metal oxidizing agent comprises ferricnitrate, and the amino acid compound comprises glycine.
 15. A method formanufacturing a display device, the method comprising: forming an activepattern in a display area on a base substrate; forming a gate metalpattern comprising a gate electrode overlapping the active pattern;forming a source metal pattern comprising a connection pad disposed in aperipheral area surrounding the display area; forming a multiple layeron the source metal pattern, the multiple layer comprising a lower layercomprising a metal oxide, an intermediate layer disposed on the lowerlayer and comprising silver or a silver alloy, and an upper layerdisposed on the intermediate layer and comprising a metal oxide; etchingthe upper layer using a first etching composition; etching theintermediate layer using a second etching composition comprising aninorganic acid compound, a sulfonic acid compound, an organic acidcompound, a nitrate, a metal oxidizing agent, an amino acid compound,and water; and etching the lower layer using a third etching compositionto form an electrode pattern in the display area and to expose theconnection pad.
 16. The method of claim 15, wherein the source metalpattern has a single-layer structure or a multiple-layer structure, thesource metal pattern comprising aluminum.
 17. The method of claim 15,wherein the metal oxide comprises at least one selected from the groupconsisting of indium oxide, zinc oxide, tin oxide, indium tin oxide andindium zinc oxide.
 18. The method of claim 15, wherein the secondetching composition comprises: 1 wt % to 13 wt % of the inorganic acidcompound, 0.1 wt % to 7 wt % of the sulfonic acid compound, 30 wt % to55 wt % of the organic acid compound, 1 wt % to 17 wt % of the nitrate,0.01 wt % to 0.09 wt % of the metal oxidizing agent, 0.1 wt % to 7 wt %of the amino acid compound, and a remainder of the second etchingcomposition being water.
 19. The method of claim 15, wherein: theinorganic acid compound comprises nitric acid, the sulfonic acidcompound comprises methanesulfonic acid, the organic acid compoundcomprises citric acid and acetic acid, the nitrate comprises calciumnitrate and ammonium nitrate, the metal oxidizing agent comprises ferricnitrate, and the amino acid compound comprises glycine.
 20. The methodof claim 15, further comprising connecting a driving chip, whichgenerates a driving signal, to the connection pad.